reverse mode: support wildcard exclude (--exclude-wildcard)

This adds support for gitignore-like wildcards and exclude patters in
reverse mode. It (somewhat) fixes #273: no regexp support, but the
syntax should be powerful enough to satisfy most needs.

Also, since adding a lot of --exclude options can be tedious, it adds
the --exclude-from option to read patterns from a file (or files).

1 files changed, 66 insertions, 0 deletions

diff --git a/internal/fusefrontend_reverse/excluder.go b/internal/fusefrontend_reverse/excluder.go
new file mode 100644
index 0000000..5c0941a
--- /dev/null
+++ b/internal/fusefrontend_reverse/excluder.go
@@ -0,0 +1,66 @@
+package fusefrontend_reverse
+
+import (
+	"io/ioutil"
+	"os"
+	"strings"
+
+	"github.com/rfjakob/gocryptfs/internal/exitcodes"
+	"github.com/rfjakob/gocryptfs/internal/fusefrontend"
+	"github.com/rfjakob/gocryptfs/internal/tlog"
+
+	"github.com/sabhiram/go-gitignore"
+)
+
+// prepareExcluder creates an object to check if paths are excluded
+// based on the patterns specified in the command line.
+func (rfs *ReverseFS) prepareExcluder(args fusefrontend.Args) {
+	if len(args.Exclude) > 0 || len(args.ExcludeWildcard) > 0 || len(args.ExcludeFrom) > 0 {
+		excluder, err := ignore.CompileIgnoreLines(getExclusionPatterns(args)...)
+		if err != nil {
+			tlog.Fatal.Printf("Error compiling exclusion rules: %q", err)
+			os.Exit(exitcodes.ExcludeError)
+		}
+		rfs.excluder = excluder
+	}
+}
+
+// getExclusionPatters prepares a list of patterns to be excluded.
+// Patterns passed in the -exclude command line option are prefixed
+// with a leading '/' to preserve backwards compatibility (before
+// wildcard matching was implemented, exclusions always were matched
+// agains the full path).
+func getExclusionPatterns(args fusefrontend.Args) []string {
+	patterns := make([]string, len(args.Exclude)+len(args.ExcludeWildcard))
+	// add -exclude
+	for i, p := range args.Exclude {
+		patterns[i] = "/" + p
+	}
+	// add -exclude-wildcard
+	copy(patterns[len(args.Exclude):], args.ExcludeWildcard)
+	// add -exclude-from
+	for _, file := range args.ExcludeFrom {
+		lines, err := getLines(file)
+		if err != nil {
+			tlog.Fatal.Printf("Error reading exclusion patterns: %q", err)
+			os.Exit(exitcodes.ExcludeError)
+		}
+		patterns = append(patterns, lines...)
+	}
+	return patterns
+}
+
+// getLines reads a file and splits it into lines
+func getLines(file string) ([]string, error) {
+	buffer, err := ioutil.ReadFile(file)
+	if err != nil {
+		return nil, err
+	}
+	return strings.Split(string(buffer), "\n"), nil
+}
+
+// isExcludedPlain finds out if the plaintext path "pPath" is
+// excluded (used when -exclude is passed by the user).
+func (rfs *ReverseFS) isExcludedPlain(pPath string) bool {
+	return rfs.excluder != nil && rfs.excluder.MatchesPath(pPath)
+}